[gnome-builder] hover: fix potential crash with DnD

[Christian Hergert <chergert src gnome org>]

commit 15b7ecfc1891f64ee9b845636eaa58b620210dbb
Author: Christian Hergert <chergert redhat com>
Date:   Tue Sep 8 17:07:07 2020 -0700

    hover: fix potential crash with DnD
    
    Fixes #1177

 src/libide/sourceview/ide-hover.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/src/libide/sourceview/ide-hover.c b/src/libide/sourceview/ide-hover.c
index 218fb9644..e34150d4c 100644
--- a/src/libide/sourceview/ide-hover.c
+++ b/src/libide/sourceview/ide-hover.c
@@ -140,10 +140,12 @@ ide_hover_popover_enter_notify_event_cb (IdeHover               *self,
   g_assert (IDE_IS_HOVER (self));
   g_assert (event != NULL);
   g_assert (IDE_IS_HOVER_POPOVER (popover));
-  g_assert (self->state == IDE_HOVER_STATE_DISPLAY);
 
-  self->state = IDE_HOVER_STATE_IN_POPOVER;
+  /* Possible with DnD dragging? */
+  if (self->state != IDE_HOVER_STATE_DISPLAY)
+    return GDK_EVENT_PROPAGATE;
 
+  self->state = IDE_HOVER_STATE_IN_POPOVER;
   dzl_clear_source (&self->dismiss_source);
 
   return GDK_EVENT_PROPAGATE;